Manage your subscription

The fish that kill with special-ops signals

25 June 2014

THE secret of war lies in the communications. So said Napoleon, but lionfish know it too. It turns out the colourful predators display a kind of sophisticated semaphore with their fins in order to recruit others in a hunt. And unlike any other animal, they then share out the food equally.

Oona Lönnstedt of James Cook University in Townsville, Australia, and colleagues made the discovery as they studied zebra lionfish (Dendrochirus zebra) both in the lab and on the Great Barrier Reef. In groups of up to four, the lionfish would herd their prey into a corner and share the food completely evenly. “That blew our minds,” Lönnstedt says. “It’s the first time that’s been proven in animals. Usually lions or hyenas will catch prey and share it hierarchically. The top animal takes the lion’s share.”

Closer observation revealed a distinctive fin display that only occurred prior to a group hunt, and therefore seemed to be a method of communication. Lönnstedt found that whenever there were other lionfish nearby, the fish that spotted the prey used this signal to initiate a group hunt (Biology Letters, DOI&colon; 10.1098/rsbl.2014.0281). Moreover, group hunts were more fruitful than solo efforts.

“As an intentional signal, it’s very rare. It implies that there’s a complex cognitive ability in fish,” Lönnstedt says.

This article appeared in print under the headline “Secret semaphore helps lionfish perfect a kill”

Article amended on
26 June 2014

When this article was first published, we mistakenly described Dendrochirus zebra as an invasive species.